Gas-Sensitive Characteristics of Graphene Composite Tungsten Disulfide to Ammonia.

Two-dimensional materials have outstanding application prospects in gas sensing. By constructing composite structures of various gas-sensitive materials, more-efficient and sensitive gas sensors can be further developed. After graphene is compounded with WS2, the composite material can improve the gas detection performance. In this work, the adsorption energy and the electronic properties of a graphene/WS2 structure were calculated by first-principles before and after adsorption of NH3. The calculation results indicate that the bandgap of the material was appreciably reduced after NH3 was adsorbed. In addition, a graphene/WS2 gas sensor was prepared. The response of the sensor to NH3 at a concentration of 100 ppm was 2.42% and 1.73% at 30 °C and 60 °C, respectively. Combining simulation with experiment, it is feasible to use graphene composite WS2 to detect NH3, which provides a new idea for applications of graphene and other composite materials in gas sensing.

Non-invasive evaluation for benign and malignant subcentimeter pulmonary ground-glass nodules (≤1 cm) based on CT texture analysis.

OBJECTIVES: To investigate potential diagnostic model for predicting benign or malignant status of subcentimeter pulmonary ground-glass nodules (SPGGNs) (≤1 cm) based on CT texture analysis. METHODS: A total of 89 SPGGNs from 89 patients were included; 51 patients were diagnosed with adenocarcinoma, and 38 were diagnosed with inflamed or infected benign SPGGNs. Analysis Kit software was used to manually delineate the volume of interest of lesions and extract a total of 396 quantitative texture parameters. The statistical analysis was performed using R software. The SPGGNs were randomly divided into a training set (n = 59) and a validation set (n = 30). All pre-normalized (Z-score) feature values were subjected to dimension reduction using the LASSO algorithm,and the most useful features in the training set were selected. The selected imaging features were then combined into a Rad-score, which was further assessed by ROC curve analysis in the training and validation sets. RESULTS: Four characteristic parameters (ClusterShade_AllDirection_offset4_SD, ShortRunEmphasis_angle45_offset1, Maximum3DDiameter, SurfaceVolumeRatio) were further selected by LASSO (p < 0.05). As a cluster of imaging biomarkers, the above four parameters were used to form the Rad-score. The AUC for differentiating between benign and malignant SPGGNs in the training set was 0.792 (95% CI: 0.671, 0.913), and the sensitivity and specificity were 86.10 and 65.20%, respectively. The AUC in the validation set was 72.9% (95% CI: 0.545, 0.913), and the sensitivity and specificity were 86.70 and 60%, respectively. CONCLUSION: The present diagnostic model based on the cluster of imaging biomarkers can preferably distinguish benign and malignant SPGGNs (≤1 cm). ADVANCES IN KNOWLEDGE: Texture analysis based on CT images provide a new and credible technique for accurate identification of subcentimeter pulmonary ground-glass nodules.

Association of NAT2, GSTM1, GSTT1, CYP2A6, and CYP2A13 gene polymorphisms with susceptibility and clinicopathologic characteristics of bladder cancer in Central China.

OBJECTIVE: To explore the association of polymorphisms in N-acetyltransferase 2 (NAT2), glutathione S-transferase (GST), cytochrome P450 (CYP) 2A6, and CYP 2A13 genes with susceptibility and clinicopathologic characteristics of bladder cancer in a Chinese population. METHODS: In a hospital-based case-control study of 208 cases and 212 controls matched on age and gender, genotypes were determined by PCR-based methods. Risks were evaluated by unconditional logistic regression analysis. RESULTS: It was found that significant associations of the NAT2 slow-acetylator genotype (odds ratio, OR: 2.42; 95% confidence interval, CI: 1.47-3.99), GSTM1 null genotype (OR: 1.64; 95% CI: 1.11-2.42) and GSTM1/GSTT1-double null genotype (OR: 1.72; 95% CI: 1.00-2.95) with increased risk of bladder cancer. Conversely, carriers with at least one CYP2A6*4 allele showed lower risk than the non-carriers (OR: 0.47; 95% CI: 0.28-0.79). The adjusted ORs (95% CI) for smokers with NAT2 slow-acetylator, GSTM1 null, GSTM1/GSTT1-double null genotype, and variant CYP2A6 genotypes were 2.99 (1.44-6.25), 1.98 (1.13-3.48), 2.66 (1.22-5.81) and 0.41 (0.20-0.86), respectively. Furthermore, NAT2 slow-acetylator, GSTM1 null, and GSTM1/GSTT1-double null genotypes were associated with higher tumor grade (P=0.001, 0.022, and 0.036, respectively), and only NAT2 slow-acetylator genotype was associated with higher tumor stage (P=0.007). CYP2A13 was not associated with risk or tumor characteristics. CONCLUSION: It is suggested that NAT2 slow-acetylator, GSTM1 null, GSTM1/GSTT1-double null, and variant CYP2A6 genotypes may play important roles in the development of bladder cancer in Henan area, China.